The only unbeaten team is a 10-point underdog but has been underestimated all season. They have message for old-timers in Miami hoping to celebrate a loss … not so fast.

Those Dolphins — the only team in the Super Bowl era to win every game in a season — almost saw New England join them on the mountaintop three years ago, but the Patriots lost the Super Bowl.

Last season, New Orleans won its first 13 games before losing to Dallas, and Indianapolis won its first 14 before pulling its foot from the accelerator and coasting into the playoffs.

But this season, 31 teams already have at least one loss.

Kansas City, which had last weekend off, is the last remaining undefeated team and faces a big challenge Sunday, playing the Colts in Indianapolis, where the Chiefs have lost four in a row.

Those Dolphins might be able to break out the champagne (their yearly celebration when the final unbeaten team loses) a lot sooner than they have in typical seasons. The early line has the Colts favored by 10.

Then again, not many people would have picked the Chiefs, a team that had won 10 games in the last three seasons, to open the year with victories over San Diego, Cleveland and San Francisco.

Kansas City also is loaded with former Patriots — among them offensive coordinator Charlie Weis, defensive coordinator Romeo Crennel, and quarterback Matt Cassel — who have earned advanced degrees in Colt-ology.

People have underestimated the Chiefs all season. So if those old-timers in Miami are considering opening the bubbly, the Chiefs could respond with a polite message:

Put a cork in it.

Other Week 5 games to watch:

Philadelphia at San Francisco: It's hard to believe, but San Francisco is one of the league's four winless teams. The 49ers aren't dead, though, not in the lukewarm NFC West, where every other team is 2-2. If the 49ers lose again, Mike Singletary could be the first coach of the season shown the door.

The Eagles are trying to regroup after another shakeup at quarterback, with Kevin Kolb filling in for the injured Michael Vick in Sunday's loss to Washington. The NFC East's other three teams have tough matchups, so the Eagles could make up some ground here.

Green Bay at Washington: The Redskins are riding high after winning in Philadelphia. The Packers are coming off a two-point victory over Detroit. Watch for Green Bay to try to exploit Washington's suspect pass defense and do a better job of getting receiver Greg Jennings involved.

Jennings, who led the Packers in receiving yards the last two seasons, had just two catches in each of the last two games, and was targeted on both of Aaron Rodgers' interceptions against the Lions. On one, he and Rodgers weren't on the same page on a back-shoulder throw. On the other, the ball was simply wrestled away from Jennings, something that doesn't happen often.

Minnesota at New York Jets: Brett Favre returns to face the team that once, very briefly viewed him as its conquering hero. These clubs are plenty interesting on their own, but now there's the added speculation that the Vikings and All-Pro receiver Randy Moss could soon be reunited. (Fox's Jay Glazer has reported a deal is in the works to send Moss from the Patriots back to the Vikings.) That would satisfy Favre's longstanding dream to play with Moss, and — especially when Sidney Rice returns from his hip injury — certainly would solve the Vikings' need for more playmakers on offense. Meanwhile, the Jets get receiver Santonio Holmes back from suspension for this one.

Players to watch

Brian Cushing, linebacker, Houston: Cushing, last season's defensive rookie of the year, rejoins the Texans after serving a four-game suspension for testing positive for a banned substance. Houston, which plays host to the New York Giants, needs all the help it can get pressuring the passer. The Texans are ranked last against the pass — largely because most of their games have been shootouts — and second against the run.

Felix Jones, running back, Dallas: Hoping to goose their productivity on the ground — they're ranked 26th in rushing — the Cowboys plan to get the ball in Jones' hands more often. Given their choice against Tennessee on Sunday, the Cowboys also would keep it out of Chris Johnson's hands.

Maurice Jones-Drew, running back, Jacksonville: The former UCLA standout faces Buffalo, the league's worst rushing defense, and has scored a touchdown on the Bills the last four times he has faced them. Against the Colts last Sunday, Jones-Drew rushed for 105 yards in 26 carries with a touchdown.